Insulator.



J. A. SANDFORD, h.

' INSULATOR.

APPL IOATION FILED DEO.16, 1911.

Patented Apr. 14, 191 4.

1 NITED; STATES PATENT OFFIGE.

' Iosn'rri unison senn'ronn,

JR., OF EAST LIVERPOOL, OHIO, ASSIGNOB. TO THE I a 'rnomas AND sonscom'amr', or EAST L'rvnnrooL, 01110, A conronarron or omo.

msunaron.

Patented Apr. 14, 1914.

Application filled December 16, 1911. Serial No. 666,278.

To all whom it mayv concern Be. it known that I, Josnrn ADDISON SANnroan, J r., of America, and residing at East Liverpool,

in the county of Columbiana and State of Ohio, have invented a certain new and useful Improvement in Insulators, of which the following is a specification.

My present invention relates to insulators and particularly to an insulator of the pin type, the object of my invention being to provide an insulator of this type adapted to ficiency, it has been carry electric power cables of very high voltage.

In the accompanying drawing, an exemplary embodiment of my invention is illustrated, half in side elevation and half in vertical section.

The present practice in the stringingv of power cables of high voltage is to hang the same from insulators of the suspension type.

Insulators of the lattertype consist of sev-- eral porcelain diskssuspended one under the other by means of metal units, comprising hooks and caps carried respectively by the upper and lower insulators. The presence of the considerable amount ofmetal which is thus necessary at the joint between the insulation very great.

The present insulator is of the pin type and comprises a cap unit A, the top of which is specially shaped to ,afiord a diametral cable groove (1. and a circumferential securing wire groove 1), tied in position in the groove a. Beneath thecap insulator A, I provide a series of interchangeable bell insulator units B, the number of which may be multiplied to the extent necessary to secure the desiredprotective insulation space between the cable and in. The units B are of any desired size and thickness,- but are designed r that the same, the juxtaposed or meeting upper'portion of eachshall iit well up with-- inthe 'lower'portion of the unit above the faces of the a citizen of the United States leakage from the cable by which the cable may be units B being provided with recesses or ribs 0 or d to insure a mechanical jointure with the cement C interposed between the meetmg faces. It will be noted that the top of one bell B extends up within the superposed bell B to a point a little above the lower edge of the cementing space between the latter and its superposed bell, so that atthis point there is a thickness of the walls of three bells and two layers of interposed cement, while at no point in the composite insulator structure is there a thickness of less than the walls of two units.' At the same time it will be noted that the diaphragm D at the upper end of the bell forms a strut extending between the opposite sides of one unit at its joint with its superposed unit. It is thus obvious that each of the joints between the various B units of the insulator is one of great mechanical strength.

The pin P on which the insulator is mounted, extends only into' thefbcttom unit- B, and is therefore very-fanre'movedfrom the transmission cable, and due to this fact the tendency of the insulator to puncture is greatly reduced. In fact the construction is such that care has only to be taken that a sufiicient distance is obtained by the use of a suitable number of the-B units to minimize to the pin under dry conditions, and arcing from the cable to the pin under rain or storm conditions.

The absence ofany metallic elements and the consequent absence of the condenser effect, present in insulators of the suspension type, greatly increases the electrostatic capacity of the present insulator and it is possible to sure of 120,000 volts.

From a manufacturers standpoint the value of the present insulator is readily seen, since the cap unit A may be used with as many or as few B units as theline voltage may require. In view of the fact that the B units are identical in form, they may be manufactured in large quantities and used for building up insulators of only the particular capacity which may be required.

I claim as my invention 1. A built-up insulator comprising interchangeable, nested units, top-closure diaphragms for. each of said units, said diaphragms build up an insulator of this type to" carry a cable charged under a working pres-. '95

being spaced apart and serving to material uniting the units, the joint between one unit and its superposed unit overlapping the joint between the latter and the unit -next above, for thepurpose described.

A built-up insulator comprising a capunit shaped to receive an electric cable, a

series "of interchangeable nested insulator units beneath the same, top-closure diaphragms for said units, said diaphragms being spaced apart to form inclosed air chambers eementitious material'uniting the unit-s,v

the joint between one unit and its superposed unit. overlapping the joint between the latter and the unit next above, the bot-v tom unit of the series receiving the support-i 15,

t\vo subscribing Witnesses.

JOSEPH ADDISON SANDFORD, R.

Witnesses:

R. L. GAwooD, R. R. ORR. 1" 

